Lubricating oil cleaning system and lubricating oil cleaning method

Abstract

A lubricating oil cleaning system (100) can clean a stock liquid (DO), into which ammonia has been mixed, to produce a lubricating oil (LO). The lubricating oil cleaning system (100) is provided with: an engine (200); a lubricating oil cleaning machine (1) that separates a stock liquid (DO) that contains a lubricating oil (LO) that has been used in the engine (200) into a heavy liquid that contains ammonia and a light liquid that is the lubricating oil (LO) which was cleaned; a water supply means (110) that supplies water into a separation chamber (SZ) of the lubricating oil cleaning machine (1); and a control means that performs first control, in which the content of the separation chamber (SZ) is fully discharged, and second control, in which water is supplied by the water supply means into the separation chamber after the first control.

Description

Lubricating oil cleaning system and lubricating oil cleaning method

[0001] The present invention relates to a lubricant oil purification system and method for purifying lubricant oil containing ammonia.

[0002] As a countermeasure against global warming, ammonia fuel, which does not emit carbon dioxide, a greenhouse gas, when burned, has attracted attention as a promising energy source for realizing a carbon-neutral society. In recent years, the practical application of ammonia gas turbine engines and ammonia-compatible engines that can be operated using liquid ammonia as ship fuel has been promoted. Furthermore, development is also underway for the operation of ammonia-fueled ships, so-called zero-emission ships, which use liquid ammonia as fuel (see, for example, Patent Documents 1 and 2).

[0003] Patent No. 6934555 Patent No. 6940727

[0004] When liquid ammonia is used in engines of ships, etc., there is a problem that unburned ammonia gas in the engine is mixed into the lubricating oil or dissolves in the water in the lubricating oil. Specifically, dissolution of water in the lubricating oil occurs when condensation occurs during engine operation or after the engine is stopped, causing water to mix into the lubricating oil. If the engine is operated without removing ammonia from the lubricating oil, the ammonia concentration in the engine increases. Ammonia is corrosive, so materials exposed to ammonia water or an ammonia atmosphere are subject to corrosion.

[0005] In addition, in a lubricating oil purifier that separates a stock solution containing used lubricating oil into a heavy liquid and a light liquid (lubricating oil), if ammonia is mixed into the stock solution, the specific gravity of the heavy liquid decreases, resulting in a decrease in the removal rate of the heavy liquid, and there is a risk of problems such as the light liquid (lubricating oil) leaking from the heavy liquid side or the heavy liquid being mixed into the light liquid. Also, in order to remove solids accumulated in the lubricating oil purifier, the entire content of the separation chamber of the lubricating oil purifier may be discharged, but if ammonia is mixed into the stock solution, there is a possibility that ammonia gas or droplets of ammonia water will remain in the separation chamber after the total discharge (total discharge).

[0006] An object of the present invention is to solve the above-mentioned problems and to provide a lubricating oil purification system and a lubricating oil purification method that can remove ammonia gas or ammonia water remaining in a lubricating oil purifier after total discharge.

[0007] In order to solve the above problems, the present invention provides a lubricating oil purification system capable of purifying a stock solution containing ammonia or ammonia water into lubricating oil, and includes an engine, a lubricating oil purifier that separates the stock solution containing the lubricating oil used in the engine into a light liquid that is the purified lubricating oil and a heavy liquid that contains ammonia, a water supply means that supplies water into a separation chamber of the lubricating oil purifier, and a control means that performs a first control to discharge all of the contents in the separation chamber and a second control to supply water into the separation chamber by the water supply means after the first control.

[0008] The present invention also provides a lubricating oil purification method capable of purifying a stock solution containing ammonia or ammonia water into lubricating oil, comprising a centrifugal separation process for separating the stock solution containing the lubricating oil used in an engine into a light liquid which is the lubricating oil purified by a lubricating oil purifier and a heavy liquid which contains ammonia, a total discharge process for discharging all of the contents in the separation chamber of the lubricating oil purifier, and a water supply process for supplying cleaning water into the separation chamber.

[0009] The lubricating oil cleaning system and lubricating oil cleaning method of the present invention can remove ammonia gas or ammonia water remaining in the lubricating oil cleaner after total discharge.

[0010] 1 is a block diagram showing a lubricant oil purification system and a lubricant oil purification method according to an embodiment of the present invention; FIG. 2 is a partial cross-sectional view showing a lubricant oil purifier; FIG. 3 is a cross-sectional view of a rotor of the lubricant oil purifier; FIG. 4 is a process diagram showing the working steps of the lubricant oil purification method according to an embodiment of the present invention; FIG. 5 is a schematic view showing the state of a separation chamber when normal lubricant oil is centrifuged in the lubricant oil purifier; FIG. 6 is a schematic view showing the state of a separation chamber when lubricant oil mixed with ammonia is centrifuged in the lubricant oil purifier; FIG. 7 is a diagram showing the lubricant oil purification method according to an embodiment of the present invention, showing the state inside the separation chamber and the frame after total discharge; FIG. 8 is a diagram showing the lubricant oil purification method according to an embodiment of the present invention, showing the state where cleaning water has been injected into the separation chamber; FIG. 9 is a diagram showing the lubricant oil purification method according to an embodiment of the present invention, showing the state where cleaning water in the separation chamber is discharged again total and cleaning water is sprayed into the frame.

[0011] A lubricant cleaning system 100 and a lubricant cleaning method according to an embodiment of the present invention will now be described in detail with reference to FIGS.

[0012] <Lubricant Oil Purification System> The lubricant oil purification system 100 shown in FIG. 1 is a purifier for purifying lubricant oil LO (see FIG. 3), fuel oil, bilge water, etc. used in an engine 200 installed on a ship or in a limited installation space on land (e.g., a remote island power plant, an existing power plant, etc.) to make it reusable. Hereinafter, as an example of the lubricant oil purification system 100 according to the present invention, a case will be described in which the lubricant oil LO used in an engine 200 that burns liquid ammonia as fuel is used as the target liquid (stock liquid DO) to be purified. In an engine 200 that uses liquid ammonia as fuel, there is a possibility that stock liquid DO containing sludge SG, ammonia, ammonia water AW, etc. may be discharged into the lubricant oil LO within the engine 200.

[0013] The lubricating oil purification system 100 includes a lubricating oil purifier 1 as shown in FIGS. 1 and 3. The lubricating oil purifier 1 separates a raw liquid DO containing lubricating oil LO contaminated with ammonia water AW into a light liquid (purified lubricating oil LO), a heavy liquid (ammonia water AW containing ammonia), and sludge SG (solids). The lubricating oil purifier 1 may be, for example, a three-phase separation plate-type centrifuge. More specifically, as shown in FIGS. 1 and 3, the lubricating oil purification system 100 mainly includes a lubricating oil tank 300, a lubricating oil supply pump P1, a heater 400, the lubricating oil purifier 1, a sludge tank 700, a water supply line 110 (water supply means), a heavy liquid discharge line 120 (drainage means), a separator inlet line 130, a sludge discharge line 160, a working water and wash water discharge line (water discharge means) 190, and a control device 900. The lubricant oil purification system 100 is installed in a ship. In the lubricant oil purification system 100, a path for supplying the undiluted oil DO discharged from the engine 200 to the lubricant oil purifier 1 is formed by a lubricant oil discharge line 150, a lubricant oil tank 300, and a separator inlet line 130. A pressure sensor 810, a moisture detection sensor 820, and an ammonia sensor 830 may be installed in the light liquid discharge line 140.

[0014] <Engine> The engine 200 shown in FIG. 1 is a marine diesel engine installed on a ship, which uses liquid ammonia as fuel, which has zero emissions of carbon dioxide, a greenhouse gas, and may be a turbine engine. The engine 200 is composed of a mechanism in which the crankshaft and pistons are connected only by connecting rods. In the engine 200, lateral pressure, which is a lateral force, is generated on the pistons, causing uneven wear in the cylinders. For this reason, the engine 200 uses lubricating oil LO to facilitate smooth piston movement. The engine 200 may also be one that burns a mixture of liquid ammonia and a fossil fuel such as natural gas.

[0015] <Lubricant Oil Discharge Line> The lubricant oil discharge line 150 shown in Fig. 1 is a piping line for sending lubricant oil LO (undiluted oil DO) used in the engine 200 to the lubricant oil tank 300. One end of the lubricant oil discharge line 150 is connected to the engine 200, and the other end is connected to the lubricant oil tank 300.

[0016] <Lubricant Tank and Lubricant> As shown in FIG. 1 , the lubricant tank 300 is a tank for storing a stock solution DO containing lubricant oil LO used by the engine 200. The stock solution DO supplied from the engine 200 to the lubricant tank 300 contains ammonia derived from ammonia fuel. For this reason, the lubricant tank 300 is a tank with a lid (a sealed tank) that prevents ammonia vaporized from the stock solution DO from leaking out of the lubricant tank 300. The stock solution DO also contains ammonia water AW that was mixed in by the engine 200. The specific gravity of the stock solution DO is 0.90 to 0.96.

[0017] <Ammonia water and water> Ammonia water AW is an alkaline aqueous solution in which ammonia (NH3) is dissolved in water W. Ammonia water AW has a distinctive pungent odor. Ammonia water AW may corrode the fluororubber O-rings and copper alloy heavy liquid and light liquid impellers used in the lubricating oil purifier 1. For this reason, it is preferable that these parts are made of corrosion-resistant materials.

[0018] Furthermore, the specific gravity of ammonia water AW is lighter than the specific gravity (1.0) of water W. For example, the specific gravity of ammonia water AW is 0.9 when the ammonia concentration is about 28%, and 0.88 when the concentration is about 35%. Since the specific gravity of ammonia water AW changes depending on the ammonia concentration, the position of the separation boundary surface SB in the separation chamber SZ of the lubricant oil purifier 1 moves in the radial direction, as shown in Figure 3.

[0019] <Contains Liquid Supply Line> The separator inlet line 130 shown in FIG. 1 is a piping line for supplying the concentrate DO (sludge SG, ammonia water AW, and ammonia-mixed lubricating oil LO) stored in the lubricating oil tank 300 to the lubricating oil purifier 1. The separator inlet line 130 includes a heater upstream line 131 extending from the lubricating oil tank 300 to the heater 400 and a heater downstream line 132 extending from the heater 400 to the lubricating oil purifier 1. The heater upstream line 131 is provided with a lubricating oil supply pump P1. The heater downstream line 132 is provided with a three-way valve 134. The switching of the three-way valve 134 is controlled by the control device 900. As shown in FIG. 3, the separator inlet line 130 may also be provided with a water storage tank 139, a water supply line 136, an addition means 135, and a mixing means 137.

[0020] <Water Storage Tank and Water Supply Line> The water storage tank 139 is a tank for storing water W to be supplied to the adding means 135. The water storage tank 139 is connected to the adding means 135 via a water supply line 136. Note that the adding means 135 may be connected to the water supply line 110 instead of the water storage tank 139 and the water supply line 136, and may be supplied with water from the water supply line 110.

[0021] <<Addition Means>> The addition means 135 is a device for adding water W to the stock solution DO in the separator inlet line 130. The addition means 135 is, for example, composed of a nozzle connected to the separator inlet line 130. The addition means 135 is installed downstream of the heater 400 in the separator inlet line 130. The stock solution DO in the heater downstream line 132 downstream of the addition means 135 is mixed with ammonia water AW, ammonia, water W added from the addition means 135, etc. In the separator inlet line 130, downstream of the addition means 135 or in the addition means 135, a mixing means 137 for mixing the water W and the stock solution DO is provided.

[0022] <Mixing Means> The mixing means 137 is a mixer for mixing the raw liquid DO in the separator inlet line 130 with the water W added by the adding means 135. The mixing means 137 is made up of a static mixer (stationary mixer) provided in the separator inlet line 130. The static mixer disturbs the flow of liquid in the piping, thereby bringing the ammonia contained in the raw liquid DO into contact with the water W added by the adding means 135 and promoting the production of ammonia water AW, and is made up of piping equipped with stirring elements and impellers that divide, invert, rotate, etc. the fluid.

[0023] <Lubricant Oil Supply Pump> The lubricant oil supply pump P1 is a pump for sending the stock solution DO in the lubricant oil tank 300 to the lubricant oil purifier 1 via the separator inlet line 130. The lubricant oil supply pump P1 is installed between the lubricant oil tank 300 and the heater 400 in the heater upstream line 131, and the stock solution DO in the lubricant oil tank 300 is supplied to the lubricant oil purifier 1 via the heater 400 and the three-way valve 134. As shown in FIG. 1 , the stock solution DO in the heater upstream line 131 is mixed with ammonia water AW and ammonia.

[0024] <Heater> The heater 400 is an oil heater that heats the lubricating oil LO (undiluted oil DO) to be sent to the lubricating oil purifier 1. The heater 400 is provided between the lubricating oil supply pump P1 and the three-way valve 134 in the separator inlet line 130. The heater 400 heats the lubricating oil LO to, for example, about 90°C. The heater 400 heats the lubricating oil LO to reduce its viscosity, thereby increasing the efficiency of separation of either or both of the solids and moisture in the lubricating oil purifier 1.

[0025] <<Unreacted Liquid Return Line and Three-Way Valve>> The unreacted liquid return line 133 is a piping path for returning the unreacted liquid DO in the separator inlet line 130 to the lubricating oil tank 300. The unreacted liquid return line 133 can return the flow of unreacted liquid DO to the lubricating oil tank 300 by switching the three-way valve 134 when necessary for operating the lubricating oil purifier 1 when discharging sludge, when an alarm occurs, or when replacing water or sealing water is introduced.

[0026] <Light Liquid Discharge Line> The light liquid discharge line 140 is a flow path for returning the lubricating oil LO (light liquid) purified by the lubricating oil purifier 1 to the lubricating oil tank 300. The light liquid discharge line 140 consists of a piping path from the discharge port of the lubricating oil purifier 1 to the lubricating oil supply port of the lubricating oil tank 300.

[0027] <Lubricant Oil Purifier> The lubricant oil purifier 1 is a device for separating / removing sludge SG (solids) and ammonia water AW contained in the raw liquid DO supplied from the lubricant oil tank 300 from the lubricant oil LO. The lubricant oil purifier 1 may be, for example, a separator plate-type centrifuge that separates the raw liquid DO into three phases: liquid (light liquid), liquid (heavy liquid), and solids, by the centrifugal force of a rotor 3 (see FIG. 2) rotating at high speed. Inside the ship, the lubricant oil purifier 1 is connected to a separator inlet line 130 and a light liquid discharge line 140.

[0028] Next, the lubricating oil purifier 1, which is a separator plate type centrifuge, will be described in more detail with reference to Figures 2 and 3. As shown in Figure 3, the lubricating oil purifier 1 is a centrifuge (centrifugal settler) in which a number of separator plates 13, each made of a truncated cone-shaped thin plate, are stacked at intervals in the axial direction of the guide cylinder 5 inside the rotor 3. The lubricating oil purifier 1 has a mechanism for discharging sludge SG accumulated on the inner wall of the rotor 3 to the outside by opening and closing the valve cylinder 6. The lubricating oil purifier 1 includes a rotor shaft 2, a rotor 3, a guide cylinder 5, a separation chamber SZ, a valve cylinder 6, a light liquid discharge section 9 (see Figure 2), and a heavy liquid discharge section 15.

[0029] <Rotating Shaft> As shown in FIG. 2 , the rotating shaft 2 has a gear portion 2 a that meshes with a speed-increasing gear 21 that is rotationally driven by an electric motor (not shown), and is rotated by the electric motor (not shown) via the speed-increasing gear 21.

[0030] <Rotating Body> As shown in Fig. 3, the rotating body 3 is attached to the rotating shaft 2 and rotates at high speed around the rotating shaft 2. The rotating body 3 has a shape in which an upper half is a roughly truncated cone-shaped portion and a lower half is a large-diameter cylindrical portion whose diameter is larger than the large diameter of the truncated cone-shaped portion, which are integrally formed. The rotating body 3 is fixed to the rotating shaft 2.

[0031] <Liquid Inlet Pipe> As shown in Figure 3, the liquid inlet pipe 4 is a pipe for supplying the undiluted liquid DO (lubricating oil LO used in the engine 200) and water W into the interior of the rotor 3. The liquid inlet pipe 4 is provided above the center of the rotor 3. The water supply line 110 and the separator inlet line 130 (see Figure 2) are connected to the upstream side of the liquid inlet pipe 4. In addition, the water W to be supplied to the separation chamber SZ of the lubricating oil purifier 1 is introduced into the rotor 3 from the water supply line 110 via the liquid inlet pipe 4.

[0032] <Guide tube> The guide tube 5 is a member for guiding the stock solution DO and water W introduced into the rotor 3 from the liquid inlet pipe 4 from the lowest part of the rotor 3 to the separation chamber SZ. The guide tube 5 is made of a cylindrical body with a flared shape and is provided in the center of the rotor 3.

[0033] <Separation Chamber> As shown in Figure 3, the separation chamber SZ is a chamber for separating the centrifugal force-applied raw liquid DO into its individual components based on differences in specific gravity. The separation chamber SZ is a circular space in cross section. A number of stacked separation plates 13 are arranged in the separation chamber SZ. The separation chamber SZ includes a separation region where the stacked separation plates 13 are arranged and a sludge accumulation region at the outermost diameter of the rotor 3. As the raw liquid DO introduced into the separation chamber SZ flows upward through the gaps between the separation plates 13, the sludge SG, which has the highest specific gravity, accumulates in the outer sludge accumulation region, while the heavy liquid (ammonia water AW or water W), which has a lower specific gravity than the sludge SG, moves to the region between the sludge accumulation region and the separation region, and the light liquid (lubricating oil LO), which has the lowest specific gravity, moves toward the center of the rotor 3. The light liquid (purified lubricating oil LO) is discharged to the outside from the light liquid discharge section 9 (see Figure 2) located at the top of the rotor 3. The ammonia water (heavy liquid) AW separated in the separation chamber SZ is discharged to the outside through the heavy liquid discharge line 120 and the leak detector 840 from the heavy liquid discharge section 15 formed between the water receiving plate TD and the inner wall of the upper part of the rotating body 3.

[0034] <Valve Cylinder> The valve cylinder 6 is a valve element that opens and closes the sludge discharge port 12 (the portion that presses against the valve packing 7). When the pilot valve V is opened to drain the water below the valve cylinder 6, the valve cylinder 6 descends, opening the sludge discharge port 12 and discharging the sludge SG. Below the valve cylinder 6, there is provided a working water supply port 61 that supplies working water WW for opening and closing the valve cylinder.

[0035] 2, the light liquid discharge section 9 is a section for discharging the lubricating oil LO (light liquid) separated in the separation chamber SZ to the outside. A light liquid discharge line 140 is attached to the light liquid discharge section 9.

[0036] 2, the heavy liquid discharge section 15 is a section for discharging the ammonia water (heavy liquid) separated in the separation chamber SZ to the outside. A heavy liquid discharge line 120 is attached to the heavy liquid discharge section 15.

[0037] <Sludge Discharge Line> As shown in Figure 3, the sludge discharge line (sludge discharge means) 160 is a discharge path for discharging the sludge SG centrifuged in the lubricant oil purifier 1 to the outside of the lubricant oil purifier 1. The upstream side of the sludge discharge line 160 is connected to the sludge discharge port 12, and the downstream side is connected to the sludge tank 700 (see Figure 1). The sludge SG in the lubricant oil purifier 1 is released into the sludge discharge line 160, stored in the sludge tank 700, and then disposed of.

[0038] 2, the working water and cleaning water discharge line (water discharge means) 190 is a discharge path for discharging cleaning water injected into the frame 3A of the lubricating oil purifier 1. The working water and cleaning water discharge line 190 is connected on the upstream side to the lubricating oil purifier 1 and on the downstream side to the sludge tank 700 (see FIG. 1).

[0039] <Sludge Tank> The sludge tank 700 is a tank for storing the waste liquid SW and sludge SG discharged from the lubricant oil purifier 1. A vent 710 is provided at the top of the sludge tank 700 for discharging ammonia gas and the like vaporized from the waste liquid SW to the outside of the sludge tank 700. If the waste liquid SW in the sludge tank 700 is at 40°C or higher, a cooling device for cooling the waste liquid SW may be installed.

[0040] <Water Supply Line> As shown in FIG. 3 , the water supply line 110 is a water supply means for supplying water W (sealing water / displacement water) into the separation chamber SZ (inside the rotor 3). Furthermore, during operation of the lubricant oil purifier 1 (during the process of separating ammonia water AW from the stock solution DO), it is preferable to intermittently or continuously supply water W into the separation chamber SZ to adjust the specific gravity of the ammonia water AW (heavy liquid) and thereby control the position of the separation boundary surface SB. Furthermore, the water supply line 110 supplies cleaning water into the separation chamber SZ during maintenance or cleaning of the lubricant oil purifier 1. The water supply line 110 is provided with a valve SV3 (not shown) for adjusting the supply of water W into the separation chamber SZ (inside the rotor 3). Alternatively, the supply of water W to the water supply line 110 is adjusted by controlling the valve SV3 using the control unit 910 and timer 920 based on the measurement values ​​of any of the pressure sensor 810, moisture detection sensor 820, ammonia sensor 830, and leak detector 840 described below.

[0041] <Nozzle Water Supply Line> As shown in FIG. 2, the nozzle water supply line 111 is a water supply unit for supplying water W to the nozzles 112 .

[0042] <Nozzle> The nozzle 112 is attached to the nozzle water supply line 111 and sprays water W in a shower-like manner into the frame 3A surrounding the rotor 3. The droplets of ammonia water AW or ammonia gas discharged into the frame 3A together with the sludge SG from the sludge discharge port 12 are washed away by the water W sprayed (sprayed) into the frame 3A, and the ammonia gasified in the frame 3A dissolves in the water W sprayed (sprayed) into the frame 3A. The nozzle 112 is inserted into the upper part of the frame 3A (above the sludge discharge port 12).

[0043] 3, the heavy liquid discharge line 120 (drainage means) is a flow path through which the ammonia water AW (separated water) centrifuged in the lubricating oil purifier 1 is discharged, and is connected to the heavy liquid discharge unit 15 of the lubricating oil purifier 1. The ammonia water AW (heavy liquid) in the lubricating oil purifier 1 overflows from the heavy liquid discharge unit 15, is released into the heavy liquid discharge line 120, is stored in the sludge tank 700, and is then discarded. A leak detector 840 may be provided in the heavy liquid discharge line 120.

[0044] <Pressure Sensor> The pressure sensor 810 is a measuring instrument that measures the pressure of the light liquid discharged from the light liquid discharge section 9 of the lubricant oil purifier 1. The pressure sensor 810 is electrically connected to the control section 910.

[0045] <Moisture Detection Sensor> The moisture detection sensor 820 is a measuring instrument that measures the amount of moisture in the light liquid discharged from the light liquid discharge section 9 of the lubricant oil purifier 1. The moisture detection sensor 820 is electrically connected to the control section 910. The moisture detection sensor 820 may be omitted depending on the state of the lubricant oil LO.

[0046] <Ammonia Sensor> The ammonia sensor 830 is a measuring instrument that measures the ammonia concentration of the ammonia water AW discharged from the light liquid discharge unit 9 of the lubricant oil purifier 1. The ammonia sensor 830 is electrically connected to the control unit 910. The ammonia sensor 830 may be omitted depending on the state of the lubricant oil LO.

[0047] <Leak Detector> The leak detector 840 is a measuring instrument that mechanically measures the heavy liquid discharged from the heavy liquid discharge unit 15 of the lubricating oil purifier 1. The leak detector 840 is electrically connected to the control unit 910. The leak detector 840 may be omitted depending on the state of the lubricating oil LO.

[0048] <Control Device> The control device 900 (control means) shown in Figure 3 has the function of intermittently or continuously supplying water W to the lubricant oil purifier 1 at a preset timing or at any timing, thereby maintaining the specific gravity of the ammonia water AW (heavy liquid) in the separation chamber SZ at a predetermined value or higher. The control device 900 is configured with a control unit 910 and a timer 920. The control unit 910 is connected to the timer 920, a pressure sensor 810, a moisture detection sensor 820, an ammonia sensor 830, and a leak detector 840. The control device 900 also controls the opening and closing of various on-off valves and switching valves (such as the three-way valve 134 and valve SV3), as well as the opening and closing of the sludge discharge port 12 (the up and down movement of the valve cylinder 6). The control device 900 can perform partial discharge control, which intermittently discharges the contents in the separation chamber SZ, as well as total discharge control (first control), which discharges all of the contents in the separation chamber SZ. It also performs second control, which supplies water (cleaning water) W into the separation chamber SZ using a water supply means after total discharge, and re-total discharge control (third control), which discharges all of the water W in the separation chamber SZ after the second control.

[0049] <Clean Lubricating Oil> The clean lubricating oil is the lubricating oil LO that has been purified by the lubricating oil purifier 1. The clean lubricating oil is stored again in the lubricating oil tank 300 from the lubricating oil purifier 1 via the light liquid discharge line 140, and then supplied to the engine or auxiliary machinery (e.g., generator, boiler, etc.) of the ship.

[0050] <<Operation>> Next, the operation of the lubricant oil cleaning system 100 and the lubricant oil cleaning method according to the embodiment of the present invention will be described with reference to Figures 1 to 9. Figure 4 is a process diagram showing the working steps of the lubricant oil cleaning method according to the embodiment of the present invention.

[0051] 1 and 4, lubricating oil LO (stock oil DO) used in the engine 200 is stored in the lubricating oil tank 300 (lubricating oil storage step S1). The stock oil DO stored in the lubricating oil tank 300 is introduced into the lubricating oil purifier 1 from the separator inlet line 130 via the heater 400 and the three-way valve 134 (lubricating oil introduction step S2).

[0052] In the separator inlet line 130, a heating step S3 is performed in which the stock solution DO in the separator inlet line 130 is heated by a heater 400. When the stock solution DO (lubricating oil LO) is heated, the viscosity of the stock solution DO decreases, thereby improving the efficiency of separation of solids and moisture in the lubricating oil purifier 1. Furthermore, when the lubricating oil LO is heated, ammonia captured in the lubricating oil LO is gasified, making it easier to come into contact with the moisture in the stock solution DO.

[0053] 5 is a schematic diagram showing the state inside the rotor 3 when normal lubricating oil LO is centrifuged by the lubricating oil purifier 1. When normal lubricating oil LO (lubricating oil LO that does not contain ammonia) used in an engine that does not use liquid ammonia as fuel is centrifuged by the lubricating oil purifier 1, as shown in FIG. 5, the lubricating oil LO, water W, and sludge SG are separated.

[0054] Fig. 6 is a schematic diagram showing the state inside the rotor 3 when the lubricating oil LO mixed with ammonia is centrifuged by the lubricating oil purifier 1. That is, Fig. 6 is a schematic diagram showing the centrifugal separation step S4. In the centrifugal separation step S4, the lubricating oil LO mixed with ammonia is centrifuged by the lubricating oil purifier 1, and is separated into the lubricating oil LO, the ammonia water AW, and the sludge SG, as shown in Fig. 6.

[0055] 7 is a diagram showing a lubricant oil purification method according to an embodiment of the present invention, and is a schematic diagram showing the state when the contents of the separation chamber SZ (rotating body 3) are totally discharged (completely discharged). The total discharge step S5 is a step in which the entire contents (lubricant oil LO, ammonia water AW, and sludge SG) of the separation chamber SZ (rotating body 3) (including cases where a small amount remains) are discharged from the sludge discharge port 12 (see FIG. 2). To perform the total discharge, the control device 900 stops the supply of the raw solution DO to the separation chamber SZ (switching the three-way valve 134 to send the raw solution DO to the raw solution return line 133), and pressurizes the working water WW (see FIG. 2) to lower the valve cylinder 6, opening the sludge discharge port 12 (see FIG. 2).

[0056] When total discharge is performed, the entire amount of contents (lubricating oil LO, ammonia water AW, sludge SG, etc.) is discharged from the separation chamber SZ (rotating body 3), but droplets of ammonia gas AG and ammonia water AW may remain in the separation chamber SZ. In addition, droplets of ammonia gas AG and ammonia water AW may remain in the space between the frame 3A and the rotating body 3. It is preferable to completely remove droplets of ammonia gas AG and ammonia water AW from the rotating body 3 and frame 3A.

[0057] FIG. 8 is a diagram illustrating a lubricant oil cleaning method according to an embodiment of the present invention, and is a schematic diagram illustrating the state in which cleaning water has been injected into the separation chamber SZ (rotating body 3). That is, FIG. 8 is a schematic diagram illustrating the water supply step S6. In the water supply step S6, cleaning water is supplied into the separation chamber SZ by the control device 900. More specifically, after the total discharge step S5, as shown in FIG. 8, a predetermined amount of cleaning water (e.g., approximately 50 to 80% of the volume of the separation chamber SZ) is supplied from the water supply line 110 to the rotor 3 through the liquid inlet pipe 4. In this way, ammonia gas AG remaining in the separation chamber SZ dissolves in the cleaning water, and droplets of ammonia water AW can be incorporated into the cleaning water.

[0058] FIG. 9 is a diagram illustrating a lubricant oil cleaning method according to an embodiment of the present invention. It is a schematic diagram illustrating the state in which cleaning water is sprayed (sprayed) into the space between the rotor 3 and the frame 3A and the cleaning water in the rotor 3 is totally discharged (fully discharged). That is, FIG. 9 is a schematic diagram illustrating the cleaning step S7 and the re-total discharge step S8. If ammonia gas AG or the like remains in the space between the rotor 3 and the frame 3A, the cleaning step S7 is performed as shown in FIG. In the cleaning step S7, the control device 900 sprays (sprays) cleaning water from the nozzle 112 toward the outer surface of the rotor 3. The ammonia gas AG present in the space between the rotor 3 and the frame 3A is absorbed into the cleaning water and discharged to the sludge tank 700 through at least one of the sludge discharge line 160 and the working water and cleaning water discharge line 190. In the re-total discharge step S8, the cleaning water (cleaning water containing ammonia) in the separation chamber SZ (rotor 3) is totally discharged (fully discharged) by a control means (not shown). The washing water discharged from the separation chamber SZ in the re-total discharge step S8 is discharged to the sludge tank 700 through the sludge discharge line 160.

[0059] In this way, after the contents of the separation chamber SZ are discharged, the separation chamber SZ is filled with cleaning water, and then another total discharge is performed. This allows the ammonia remaining in the separation chamber SZ to be discharged from the system. Furthermore, by spraying (spraying) cleaning water between the rotor 3 and the frame 3A, the ammonia gas AG remaining in the frame 3A can be discharged from the system. After the re-total discharge step S8, the control device 900 switches the three-way valve 134 to resume the supply of the raw solution DO into the separation chamber SZ. In principle, the cleaning step S7 is performed after the water supply step S6 or after the re-total discharge step S8. Alternatively, the cleaning step S7 may be performed simultaneously with any of the centrifugation step S4, the total discharge step S5, the water supply step S6, or the re-total discharge step S8.

[0060] As described above, according to this embodiment, the ammonia (ammonia water AW) mixed in the stock solution DO is removed in the lubricating oil purifier 1, and purified lubricating oil LO is obtained.

[0061] The lubricating oil purification system 100 of this embodiment, as shown in, for example, FIG. 1 or FIG. 8, purifies ammonia-contaminated stock solution DO into lubricating oil LO, and includes an engine 200, a lubricating oil purifier 1 that separates the stock solution DO containing the lubricating oil LO used in the engine 200 into a light liquid that is the purified lubricating oil LO and a heavy liquid that contains ammonia, a water supply means (water supply line 110) that supplies water W into a separation chamber SZ of the lubricating oil purifier 1, and a control device 900 that performs a first control to discharge all of the contents of the separation chamber SZ and a second control to supply water W into the separation chamber SZ after the first control.

[0062] With this configuration, the lubricant oil purifier 1 can separate the lubricant oil LO, sludge SG, and ammonia water AW from the raw solution DO. In addition, the lubricant oil purification system 100 can supply water W into the separation chamber SZ during total discharge (after the entire amount is discharged), so that the water W can capture droplets of ammonia gas AG and ammonia water AW remaining in the separation chamber SZ.

[0063] Furthermore, after the second control, the control device 900 can perform a third control to discharge all of the water W in the separation chamber SZ. When the third control is performed, the ammonia gas AG and the ammonia water AW remaining in the separation chamber SZ can be discharged from the separation chamber SZ together with the water W in the separation chamber SZ, as shown in FIG. 3 or FIG. 9 .

[0064] That is, with this configuration, it is possible to reliably remove the ammonia gas AG and ammonia water AW remaining in the separation chamber SZ after the total discharge.

[0065] As shown in Figures 1 and 3, the frame 3A that covers the rotor 3 of the lubricant oil purifier 1 is provided with one or more nozzles 112 that spray cleaning water (water W) into the frame 3A.

[0066] According to this configuration, cleaning water (water W) is sprayed from the nozzle 112 into the frame 3A that covers the rotating body 3 of the lubricating oil purifier 1, so that the ammonia gas AG floating in the space between the rotating body 3 and the frame 3A can be dissolved in the cleaning water (water W).

[0067] In addition, as shown in FIG. 2, the system is provided with a working water and cleaning water discharge line 190 for discharging the cleaning water injected into the frame 3A, so that the cleaning water that has absorbed ammonia gas AG in the frame 3A can be suitably discharged outside the system.

[0068] As shown in FIG. 1 or 8, this is a lubricant oil purification method capable of purifying ammonia-contaminated stock solution DO into lubricant oil LO, and includes a centrifugation step S4 in which the stock solution DO containing the lubricant oil LO used in the engine 200 is separated into a light liquid, which is the lubricant oil LO purified by the lubricant oil purifier 1, and a heavy liquid containing ammonia; a total discharge step S5 in which, after the centrifugation step S4, the entire content of the separation chamber SZ of the lubricant oil purifier 1 is discharged; and a water supply step S6 in which water W (cleaning water) is supplied into the separation chamber SZ after the total discharge step S5.

[0069] According to this lubricating oil purification method, it is possible to separate lubricating oil LO, sludge SG, and ammonia water AW from the raw solution DO. In addition, it is possible to dissolve (capture) the ammonia gas AG and water droplets of ammonia water AW remaining in the separation chamber SZ after total discharge in water W.

[0070] Furthermore, after the water supply step S6, a total re-discharge step S8 is performed in which the entire amount of cleaning water in the separation chamber SZ is discharged, so that the ammonia remaining in the separation chamber SZ can be reliably discharged.

[0071] Also, as shown in Figure 2 or Figure 9, after the re-total discharge step S8 or after the water supply step S6, a cleaning step S7 is included in which cleaning water (water W) is sprayed into the frame 3A covering the rotating body 3 of the lubricating oil purifier 1.

[0072] According to this lubricating oil cleaning method, the ammonia gas AG remaining inside the frame 3A can be washed away.

[0073] [Modifications] The present invention is not limited to the above-described embodiments, and various modifications and changes are possible within the scope of the technical concept thereof. It goes without saying that the present invention also covers such modified and changed inventions.

[0074] In the above embodiment, as shown in FIG. 1, the case where only one lubricating oil purifier 1 is installed has been described, but a configuration in which a plurality of lubricating oil purifiers 1 are arranged in parallel may also be used.

[0075] In the above embodiment, the lubricating oil purifier 1 is illustrated as a three-phase separation type separator plate centrifuge, but a two-phase separation type separator plate centrifuge may also be used. In this case, the lubricating oil purifier 1 separates the raw liquid DO, which is the lubricating oil LO mixed with ammonia water AW, into a sludge SG containing a heavy liquid containing ammonia water AW and a light liquid, which is the purified lubricating oil LO. When a two-phase separation type separator plate centrifuge is used as the lubricating oil purifier 1, it is preferable to discharge the lubricating oil purifier 1 when the measurement value of any of the pressure sensor 810, moisture detection sensor 820, ammonia sensor 830, and leak detector 840 reaches a threshold value. Note that the moisture detection sensor 820, ammonia sensor 830, and leak detector 840 may be omitted depending on the condition of the lubricating oil LO.

[0076] 2 and 9, the case where one nozzle 112 is provided on the frame 3A has been described, but the nozzle 112 may be provided at two or more locations on the side or bottom surface of the frame 3A as appropriate.

[0077] REFERENCE SIGNS LIST 1 Lubricating oil purifier 3 Rotating body 3A Frame 100 Lubricating oil purification system 110 Water supply line (water supply means) 112 Nozzle 160 Sludge discharge line (total discharge means) 190 Working water and cleaning water discharge line 200 Engine 900 Control device (control means) AW Ammonia water DO Stock solution LO Lubricating oil SZ Separation chamber S4 Centrifugal separation process S5 Total discharge process S6 Water supply process S7 Cleaning process S8 Re-total discharge process W Water (cleaning water) WW Working water

Claims

1. A lubricating oil purification system capable of purifying ammonia-contaminated raw liquid into lubricating oil, comprising: an engine; a lubricating oil purifier that separates the lubricating oil-containing raw liquid used in the engine into a light liquid that is the purified lubricating oil and a heavy liquid that contains ammonia; a water supply means that supplies water into a separation chamber of the lubricating oil purifier; and a control means that performs a first control to discharge all of the contents within the separation chamber, and a second control to supply water into the separation chamber by the water supply means after the first control.

2. The lubricating oil purification system according to claim 1, wherein the control means performs a third control to discharge all of the water in the separation chamber after the second control.

3. The lubricant oil cleaning system according to claim 1, comprising: a frame that covers a rotating body of the lubricant oil cleaner; and one or more nozzles that spray cleaning water into the frame.

4. The lubricant oil cleaning system according to claim 3, further comprising an operating water and cleaning water discharge line for discharging the cleaning water injected into the frame.

5. A lubricating oil purification method capable of purifying ammonia-contaminated raw liquid into lubricating oil, comprising: a centrifugal separation step of separating the raw liquid containing the lubricating oil used in an engine into a light liquid which is the lubricating oil purified by a lubricating oil purifier and a heavy liquid containing ammonia; a total discharge step of discharging the entire content of the separation chamber of the lubricating oil purifier after the centrifugal separation step; and a water supply step of supplying wash water into the separation chamber after the total discharge step.

6. The lubricating oil cleaning method according to claim 5, further comprising a total re-discharge step of discharging all of the cleaning water in the separation chamber after the water supply step.

7. The lubricating oil cleaning method according to claim 6, further comprising a cleaning step of spraying cleaning water into a frame covering a rotor of the lubricating oil purifier after the total re-draining step or the water supplying step.

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